Apparatus for compacting explosive and propellent material



March 3, 1953 J. w. PERRY ETAL 2,630,041

APPARATUS FOR COMPACTING EXP SIVE ND PROPELLENT MATERIA Filed Oct. 30, 1947 W M 5 N M 2 7 6 a m M m 4A. m mm a F. w A 1 R W 7 BMW D E g m ,1 J 2 anw 0 7 2 1% N W Patented Mar. 3, 1953 UNITED STATES ENT ()FFICE APPARATUS FOR COMPACTING EXPLOS'IVE AND PROPELLENT MATERIAL James W. Perry, Newton Center, Mass, William R. Johnson, Texas City, Ten, and Joseph H. Frazer, Havre de Grace, Md.

Application October 30, 1947, Serial No. 783,033

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to apparatus for compacting or pressing finely divided explosive material, particularly finely divided solid explosive material which might be ignited, or is subject to ignition, by friction.

More particularly the present invention is concerned with the provision of apparatus for ef- Lfectively compacting finely divided propellent material in rockets or the chambers thereof intended to contain propellent material.

Among the objects of the present invention is the provision of apparatus for compacting divided solid explosive material, which might be ignited, or is subject to ignition, by friction, into chambers, such as propellent chambers of rockets, having lateral walls of metal, such as steel.

A further object of the present invention the provision of apparatus which is safe to use in compacting under high pressure finely divided solid explosive material which might be ignited by friction between relatively moving metal parts.

In order that the operation and use of the apparatus hereinafter described in detail may be fully appreciated, an example of a finely divided solid explosive material which may be effectively compacted in apparatus made in accordance with the present invention is given hereinafter, although it is to be understood that the use of the apparatus is not confined to this example of finely divided explosive material, since it may be used, as will e understood by persons skilled in the art, to press or compact many other finely divided solid explosive materials.

The example of finely divided explosive material referred to in the preceding paragraph, and which is used by way of illustration in describing the present invention, consists of an intimate mixture of the following ingredients in the indicated proportions:

1754 grams of finely divided granular potassium perchlorate previously dried in an oven at 100 to 110 0.;

482 grams of powdered or finely divided graphite;

222 grams of finely powdered metallic titanium;

109 grams of finely powdered Vinylite of VYNU grade manufactured by Carbide and Carbon Chemicals Corp;

163 grams of liquid tributyl Cellosolve phosphate.

In mixing these ingredients, it is preferred to mix intimately the solid components together as a preliminary step in the formation of the final mixture and then to mix intimately into this mixture of solid components the tributyl Cellosolve phosphate. These two mixing operations are advantageously conducted at a temperature of about 50 F. to about F. The final mixture resembles in appearance a dark colored, finely grained, slightly moist sand, which retains this appearance even after storing for several months at ambient temperatures.

The Vinylite referred to above is a high molecular weight copolymer of vinyl chloride and minor amounts of vinyl acetate. It is a thermoplastic non-heat hardening plastic material. The tributyl Cellosolve phosphate used is the neutral phosphoric acid ester of monobutyl ether of ethylene glycol of the formula OP (OCH2CH2OC4H9) 3 and physically combines as a plasticizer with the Vinylite at the temperature of pressing or compacting of the mixture. The plasticized Vinylite serves as a thermoplastic non-heathardening binder for the other components of the mixture and functions as a matrix for the other components.

Referring now to the drawings accompanying and forming part of this written description,

Figure l is a longitudinal central section of apparatus embodying the present invention;

Figure 2 is a cross-section on the line 2-2 of Figure 1;

Figure 3 is a cross-section on the line 33 of Figure l; and

Figure 4 is a portion of Figure 1 showing the relation of parts during the removal of the pressing head of the apparatus from the compacted material.

The numerals l and 2 in the accompanying drawings indicate respectively the press table and rain of a hydraulic press. The hydraulic press is of the type that its ram 2 may exert a pressure in one direction, for example downwardly as viewed in Figure 1, and a pull in the opposite direction. Hydraulic presses of this type are well known, and their details of construction are not necessary to an understanding of the present invention. The relationship of the present invention to press table I and the ram 2 of a hydraulic press of the type described is fully shown in the accompanying drawings and explained in this description.

To the press table I, is secured a holder 3 for moved from the chamber either completely as a unit or partly as a detached fragment. In the case of the specific explosive or propellant described above, a pressure of about 15,000 p. s. i. is applied for about three minutes in compacting the propellant in the propellent chamber of a rocket.

After the above mentioned cooling, the body 4 is again secured on holder 3 and the plunger 2! again brought down over the stem I8, whereupon the pin or bar 28 is passed through the two slots 21 in the plunger 2! and through the hole 20 in the stem 18. Upward motion is now imparted to the ram 2 and plungerzl, and as a consequence the lower ends of slots 21 engage the pin 28 and thereafter further upward motion of the plunger 21 pulls the stem I B and the pressing head It away from the cooled compacted material 5 and out of the chamber 5. The obturator 28' at the rear of pressing head id moves out of chamber 5 together with the pressing head I4 and stem 18. The body t is now detached from the holder 3, and the apparatus is now ready to receive another body 4 filled with finely divided explosive or propellent material to be compacted.

We claim:

1. Apparatus for compacting finely divided solid material, which is subject to ignition by friction, into a chamber formed by a cylindrical body open at one end and having lateral metallic walls, comprising a circular, metallic pressing head having a diameter slightly smaller than the inside diameter of said cylindrical body, a stem having a transverse bore, said stem being afiixed to said pressing head in coaxial alignment therewith, a non-metallic obturator fitting over said stem having a diameter as nearly equal to the inside of diameter of said cylindrical body as pos sible to block passage of said material between i positioned in predetermined relationship to said transverse bore.

2. The apparatus according to claim 1 wherein said slots and said transverse bore are so positioned with respect to each other that said transverse bore registers about midway between said slots with said plunger abutting against said obturator.

3. Apparatus for compacting finely divided, solid material, which is subject to ignition by friction, into a chamber formed by a cylindrical body open at one end and having, lateral metallic walls, comprising first means having a diameter smaller than the inside diameter of said body to produce a clearance between said walls and said first means, a cylindrical stem afilxed to said first means nearer said opened end and in axial alignment therewith, second means made of hard, dense, non-gritty material adjacent said first means nearer said open end and having a diameter as nearly equal to the inside of said body as possible to prevent escape of said material through said open end and yet permit free axial movement of said second means with in said chamber, said second means having a bore large enough to receive said stem, and third means for applying pressure to said second means whereby pressure is imparted to said first means, said third means including a cylindrical plunger having a diameter approximately equal to the diameter of said first means and a central bore of a diameter slightly larger than said stem whereby said plunger may slide freely over said stem and abut said second means, said stem and said plunger including each one diametric hole.

JAMES W. PERRY. WILLIAM R. JOHNSON. JOSEPH H. FRAZER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,457,988 Miller June 5, 1923 1,518,272 Olmstead Dec. 9, 1924 2,168,396 Davis Aug. 8, 1939 2,287,277 Ryder June 23. 1942 2,380,167 Grim July 10, 1945 

